Improvement in oases foe eotaey pumps



I @enregistre-@strut @ffice Letters Patent No. 81,010, dated August 11, 1868.

IMPROVEMENT IN GASES FOB. ROTARY PUMPS.

' eige rlgrtul referat it it tlgtsettttas zient mit mating :mi nf its time.

TO ALL WHO-M ITMAY- GONCERN:

, Beit known that we, I. H. ROOTS and F. M. ROOTS, of Connersville, in the county Aof Fayette, and State of Indiana, have invented a new and useful Improvement in Constructing Cases or Shells for Rotary Blowers; and we do hereby declare that the following'is a full, clear, and exact description thereof, which will enable those skilled in the art to make and use the saine, reference being had tothe accon'ipanyingl drawings, forming part of this specication.Y i

The object of this invention is, firstly, to avoid the necessity of boring out the interior concaveeurface of the shell or case; and, secondly, to obviate the necessity of facing or planing the end or head-plates of the case, both of which have always heretofore 'been done in cases of this kind, which requires the case to beicast in separate parts, while b'r our Amethod the case is cast in one entire piece.

We thus obtain a case oflgreater strength and with less material, and 'at the same time,'by our method of fitting up, we obtain a case of greater accuracy than those fitted up in the ordinary manner, and at a great saving of labor and expense. i

And the invention consists in fitting up and rendering the interior of the case true, so as to accurately fit the. rotating' pistons abutments, bythe use of plaster of Paris, soft metal, or other suitable substance ormat'crial, and also in the use of secondary or inside heads, against which the ends of the pistons work'.

Figure represents a longitudinal vertical section "of the blower, through the line x :c of iig. 2.

Figure 2 is a vertical cross-section of iig. 1, through the line yy.

Similar letters of reference indicate corresponding parts.

A is'the case or shell, with two accurately-described arcs of circles, BB, which correspond with th'e circumference of the abutment-pistons.

C C represent the revolving abutm'ents.

D D are the pistons.

E E represent the inner abutments cylinders.

F F representthe inside heads or plates, used in making the ends of the blowercase,true.

The case or shell A we usually cast in a single'piece, but we do not confine ourselves to' that method.

In very large blowers it would be necessary to cast the case in separate'parts.

We render the inner surface of the blower-head true, and form it into a plane at right angles with the shaft of the abutments, and perfectly parallel with each other, and equidistant from each other in all their parts, by giving theinner surface of the end-plates a coating of plaster of Paris, hydraulic cement, or other plastic or like material.

This coating may be put on with a sweep attached 'to the shafts, or by any other means by which the ends of the case may be made true and atright angles with the shaft.

In some instances we use a soft metal, as solder,I lead, or spelter, instead of the plaster of Paris, and with like results. v

The inner surfaces of the end-plates are usually cast with small projections or with recesses, for the purpose of holding thc plaster of Paris or m'etal so used firm in its place. y

The methods described for making the end-plates of the case true with plaster or metal, are used principally for blowers of a smaller size, but for blowers of a large size wegenerally use secondary or inside metal plates, which are faced or planed eff. on one side, so as to be perfectly true.`

These plates are made in their general outlines to conform to the shape of the interior of the case.

In this method the trued surfaces of the plates are placed inward, and parallel with each other, and pre- -cisely at right angles in all directions with the shafts, leaving a space between these secondary plates and the ends of the case, which space is filled with plaster, mixed tothe proper consistency, or with melted metal. When the plaster is set or the metal has become hard, these secondary plates are securely fastened in their places in any suitable manner.

These secondary plates may be fastened in their proper places by sct-scrcws, rivets, or otherwise, withoutthe {illing in with plaster or metal, as before mentioned, if desired, but are not movable after being thus placed. Having described the method of making the ends of the case true, we will now describe our method of making the circular part of the case true, so as to fit the pistons or working parts of the blower.

In making the arcs of circles (heretofore alluded to) true, we usually work from the centre of our shaftjournals, as fixed points'.

We give the inner part of the concave a coating of plaster of Paris, or other suitable material, and work A it into the proper shape andoform, while it is setting, by thc use of a sweep attached to the shafts lying in the journal-boxes of the blower. l i l While the plaster is setting, we slowly move the sweep, so as to accuratelyform the plaster or other matel Arial to therequired shape.

Instead of using the sweep, we sometimes use a cylinder, of a diameter corresponding with the sweep or circle to be described by the pistons, which cylinder is hung on a central shaft resting in the aforesaid boxes, and then pour the plaster or other material into the intervening spacebetween-the cylinder and the ease.

When the plaster has set, the cylinder is removed, leaving an arc of the required circle.

The cylindrical parts of cases used for purposes analogous to ours, have heretofore consisted of at least half circles, but the operative concave parts of our case are greatly reduced by'our particular arrangement, without any sacrifice of the value or corrcctoperation of the macliine, as the continuous contact of the parts is at all times preserved. Y

By thus reducing the arc, We save the material and labor necessary to render a largerpart of the case truc and accurate. v l I l We are thus enabled to construct a ease for rotary blowers which may be east iu one piece, having allthe advantages of strength and lightness, and at the same time eii'ecting a great saving in labor and material.

The great advantages of our method of forming these cases will be understood, when the mechanical diculties of facing olf the ends and accurately boring out the concave of an iron case in the ordinary manner are considered. I I i We not only produce a blower more accurate and effective in its operation, but at a greatly reduced cost to the purchaser, thus greatly extending the use of this most effective machine, by placing it within the reach of blacksmiths and others engaged in similar pursuits. I

We claim as new, and desire to secure by Letters Patcntv 1.- A rotary-blower case, the interior of which is rendered true and accurate by means of plastic or molten materials, substantially as set forth.

2. A rotary blower, the ends or heads of which are rendered true and accurate by means of plastic or molten materials, substantially as hercin' shown and specified.

3. A rotary blower, the concave or arcs of circles of which, and the ends or heads of which, are rendered true and accurate by the use of plaster of Paris, or other plastic material, or of molten metal, as described.

i P. I-LROOTS, F, M. ROOTS.

Witnesses:

ALEX. F. ROBERTS, WM. F. McNAMARA. 

